1, 3-diamino-2-hydroxy anthraquinone and process of making the same



ivnn' eunnnmnnn, HENRY :i.

WEILAND, AND OTTO STALLMANN, F QO'UTH MIL- WAUKEE, WISCONSIN,.ELSIG'NURS TO THE NEWPORT COMPANY, 01E CABROLLVILLE, WISCUNSIN A@OBPORATIGN OF DELAWARE.

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lilo Drawing.

We have-discovered that 3-5 -diamino4J- hydroXy-ortho-benzoyl-benzoicacid, which is described. in our co-pending application entitled 3,5-dianiino-l hydroxy-ortho benzoyl-benzoic acid'and aprocessofmakingthesame, Serial No. 151,592, filed No vember 29, -1926,-under certainconditions loses one moleculeof water and closes the ring'to'form 1,3diamino-2-hydroxy anthra- W .quinone. Thereactionis shown by thefollowing chemical equation:

The elimination of water from the 35-5- diamino-J-hydroxyorthobenzoylbenzoic acid'may be brought about by suitable .dehydrating agents, suchas sulfuric acid. We do not,fhowever, wish to limit our method to anyspecific concentration of acid v or temperature, since it has beenfound'that the elimination of water can ,be effected under variousconditions of concentration.

and temperature.

1,3-diamino-Q-hydroxyenthraqumone f m its crude form is a blackcrystalline powder.

It can be recrystallized from alcohol and is then obtained as dark redshining crystals. These crystals when heated up in a ca illary tubestart to sublime at 285. 0'. an melt under decomposition at 300-305 C.The

compound is slightly soluble in hot water,

. imparting a red color to the water, fairly soluble in boiling alcoholand more soluble in nitro-benzene.

* caustic soda or ammonia solution with a dark blue color. A solution ofthe c'om pound in dilutecaustic soda produces with sodium hydrosulfite adark red color;

Without limiting our invention to any particular procedure, thefollowing example, in w ichparts by weight are given,

1 illustrates the application of our invention 7 the preferred form:

hydroxy-ortho-benzoyl-benzoic is red again. The precipitated product,1,3

2-hydroXy-anthraquinone It is soluble in dilute Application filedNovember 29, 1926. Serial No. 151,593.

Into 1088. parts of sulfuric acid (66 Be.) are added 272 parts of3--5-diaminoacid. The mass 1s heated up to 175 185 C. and held at thattemperature for two hours. It is then cooled to 100 C. andv 1 000partsof waterareadded over a period of two hours. The dlluted mass iscooled to 4050 C. and poured mto 8000' parts of hot .water (-90? C.),stirred for 45 hours, cooled to Z 0 25 C. and filtered. The filter cakeis Washed on the filter with about 1000-'pa1'ts c5 of cold water untilthe filter cake is ractically free of mineral acid. The ca e issuspended 'in 4000 parts of hot water (90'95 C.) and -such an amount ofcaustic soda solution added as will cause the color of the mass tochange from red tojblue. A

' small amountof acetic acid is now added until the blue colordisappears and the mass diamino-2-hydroxy-anthraquinone is filtered, offat 80-90", (1, washed on the filter until free of sulfate and-dried at100 C. The crude product may be purified by crystallizing from alcohol.

We are aware that numerous details of so the process may be variedthrough a. wide range without departing from the spirit of thisinvention and we do not desire limiting the patent granted hereonotherwise than as necessitated by the prior art.

We claim'as our invention:

- 1. The process of preparing 1,3 diaminofrom, 3'-5 diamino-4 hydroxyortho benzoylbenzoic acid by means of concentrated sulfuric acid asdehydrating agent.

2. The process of preparing.1,3-diamino- 2-hydroxy-anthraquinone from3-5-diammo-4 hydroxy ortho benzoyl -)benzoic acid by eliminating watertherefrom by means of sulfuric acid as the dehydrating agent, diluting.up the condensation mass with water, filterin to remove the sulfuricacid and washing t e filtered product with water.

In testimony whereof we have hereunto subscribed our names,

IVAN GUBELMAN'N. HENRY J. wnnnnn. OTTO STALIMANN.

